Rope structure



April 28, 1942- J. A. HET ZEL 2,281,036

I RoPE STRUGTURE Filed Dec. 21, 1940 sheets-sheet 1 April 28, 1942. J.A. HETzEL.

ROPE STRUCTURE Filed Dec. 21, 1940 2 Sheets-Sheet 2 INVENTR 62. ATTO RNEYS Patented Apr. 28, 1942 UNITED s'rn'resi PA'rENT OFFICE.

ROPE STBUGTURE John A. Hetzel, Jersey City, N. J., assignor to WlrltlockCox-dage Company, VNew York, N. Y.,

a corporation of New Jersey Application December 21, 1940, Serial No.371,161

18 Claims. (Cl. 57-144)` This invention relates to rope structure orcordage and more particularly to the formation of rope strands ofilbrous or fllamentary material intended to be used as single units orlaid or twisted together with corresponding strands to form ropes,hawsers, drilling cables, cablelaid ropes and the like, the principalobject of my invention being to providea rope structure in which theindividual strands are made up of elements twisted together in such away that the length of each element in a given length of strand issubstantially equal to, or bears a predetermined relation to, the lengthof each other element, and all of the elements are twisted and arrangedto produce a strand' of maximum strength with improved durability andhandling qualities.

In conventional all-yarn rope structures heretofore produced, theindividual strands are formed by twisting together a predeterminednumber of yarns. Those, lying at or near the surface of the finishedstrand may be called the cover yarns and those lying inside the coveryarns may be called the core yarns. In ordinary practice, each yarn inthe strand, whether -it be a cover yarn or a core yam, formssubstantially a helix about the axis of the strand. The diameters of thehelices of the cover yarns are greater than those of` the core yarns,and the diameters of the helices of the outer core yarns are greaterthan those of the inner core yarns at or near the axis of'the strand.The lengths of the yarns.

in a given length of strand lare thereforeunf equal, the inner 'coreyarns being shortest and the outer cover yams being longest.` When thestrand is put under longitudinal strain in use, the pull is not equallydivided among the yarns. The inner yarns being shortest are subjected tothe severest strain. The outer yarns being long--` est and beingcu'shioned by compression 'of the inner yarns are subjected to the leaststrain. As a result, the inner yarns are subjected to greater strainthan the outer yarns, and in case of excessive strain the inner yarnswill brealr first and the rupturing will proceed outwardly through thecore yarns to the cover yarns.

The problem of providingi'a strand structure that 1will impose' equalstrain' simultaneously upon all of the yarns or elements of the strandand permit them all to exert simultaneously their full tensiie strength,has long challenged the ingenuity of rope makers. A number of proposalshave been made for solving the prob-` lem but without practical success.

or a predetermined percentage of, that of the` same length ofl strand.

yams that are symmetrically twisted around the axis of the unit. In agiven length of such a. structure. the units are all of equal lengthbecause they are arranged in helices of equal diameter around the axisof' the strand; the smaller elements or yams comprising each single unitare all of equal length because they are arranged in helices 'of equaldiameter around the axis of that unit; in consequence, all of theelements or yarns, so arranged in any given length of strand, are of thesame substantial length. The

Symmetry of the structure and the equal length of yarns or rope elementscomprising it, enable all ofthe yarns or rope elements to pull togetherequally and simultaneously, strand| structureof maximum tensiiestrength.

The units may be made of yarns or groups of yarns or slivers or` groupsof sllvers or the like. The units may, if desired, be pretwisted in thesame direction in which they are formed in the strand or in the oppositedirection.

The strand may be supplied with cover yarns of any suitable size orother elements such -as ply goods, 'and the pitch of the cover yams orelements may be correlated to the compound twist of the core yarns orelements so as to make the length of the cover yarns or elements in agiven length of strand substantially equal to,

core yarnsor elements in the 4Fig. 5 shows a form of the invention inwhich f the unitsaremade of agroup of ply-goods;

Fig. 6 shows a form of the invention in which the core units are made ofa group of slivers; and

Figs. 7 and 8 illustrate strand structures embodying the invention inwhich the cover yarns Vhave been given a pitch greater or less than thatThe present invention is characterized by a 551 of the units comprisingthe core.

and produce a.

In the drawings and in the description that follows, the invent'ion isillustrated by reference to a strand structure that is formed to theleft and rope structure that is laid to the right. It

- will be understood, however,,that right formed aas'msc .or of suchgreater or lesser length as is desired to produce the strongest ropestructure.

It has been found by test that where the twist I imparted to each unit Ais such as to make the one preferred form of the invention, a group ofordinary right turn yarns IO are twisted together to the left to formthe unit A shown in Fig. 2. The yarns are properly arranged orguided inthe twisting operation so that they form substantially symmetricalhelices about the axis H of the unit and ai'e substantially in' contactalong the axis. The number of yarns that may be used in making such aunit is limited, but as many as eight or ten may be convenientlyemployed. A

number of units A are then twisted or'formed together to the left toproduce the strand B shown in Fig. l. The units A areproperly arrangedor guided in 'the strand forming operation so that they formsubstantially symmetrical helices about the axis V|2 of the strand andare substantially in contact along the axis or are as close thereto asthe conformation of the units A will permit.l -Good results have beensecured by using five units A in forming strand B, but obviously a-greater or smaller number may be employed within reasonable limits,having in mind that all of the units A are to be of substantialiy thesame length in a given length of strand B. From this arrangement itresults that all of the yarns 10 core yarns in a given length of strandslightly shorter, say one to three percent, Shorter, than the coveryarns in' the'same length of strand, maximum tensile strength of the.resultant rope is obtained.

Apthree-strand 51/2 inch circumference, allyarn'rope may desirably bemade in accordance with this invention, as follows: Seven regular rightturn yarns, of about 270 feet per 111/2 turns per foot, are twistedtogether symmetrically to the left, with no center yarn, through a tubeof suitable diameter, and given a pitch of about 5.1 inches. Five of theresulting units are then formed to the left, along with twenty-eightcover yarns, to produce a strand of five inch pitch, the cover yarnsbeing of the same size and material as the core yarns and ofsubstantially vthe same length in a given length of strand.

Threestrands are then laid into a rope in the customary manner. having apitch of about 5.2 inches of the strands in the rope lay; a pitch ofabout 5.8 inches of the in a given length of strand are substantiallyequal in length, and a strand structure of maximum tensile'streng'th isproduced.

V, The strand B may then preferably be laid to the right with othercorresponding strands to H form a rope or hawser, in the usual manner,and, if desired, the resulting rope may be cable-laid with othercorresponding ropes to form a cable. In each case, the resulting rope orcable will be formed-of yams, all of which are of substantially In Fig.3 is shown a rope embodying another 'preferred form of the invention. Inthis embodiment, six right tum yarns IO -are first twisted together tothe left to form a unit A, substantially.

cover yarns and core units in each strand, and a pitch of about 2.9inches of the yarns in each core' i cover yarns in a given length ofstrand, i. e.,

97-99% as long, the maximum tensile strengthis apparently achieved.

The desiredl predetermined ratio between core yarn length and coveryarnlength in a given as described above in connection with Fig. 2.

Five Iunits A are then twisted together or formed to the left, producinga core B, and at the same time cover yarns E5 'are supplied and twistedabout the core to produce a strand C, comprising a core B of units A anda cover of yarns l. The units A are appropriately guided 'in the strandforming operation so that they form subshall contribute to the fu'ilestextent to the tensile strength of the rope. it is possible by thisinlength of strand may be achieved, according to this invention, ineither or both of two ways.

Either the degree of twist used in making the units A may be increasedor decreased, as described above, or the group of units A may bepretwlsted to the right or left in making the core B before the core Bis formed with the `cover yarns to make the strand. In the latter casethe pitch of 'the cover yarns in the strand is not equal to the pitch ofthe core units in the strand.

' Fig. 7 illustrates a strand in which the cover yarns have a longerpitch in the strand than the units A of the core B, achieved bypretwisting the group of units A to the left.` Fig. 8 illustrates astrand in which the cover yarns have a shorterpitch in the strand thanthe units A vention to vprovide the desired relationship between thelength of core and cover yarns in a given length of strand without usingany difference in pitch as between theV helices formed by the coveryarns in the strand and the helices formed by the units A'in the core B.This may be accomplished by regulating the 'amount of 75 of the core B,achieved by pretwisting the group of units A to the right before theyare formed with the cover yarns to make the strand. Any desired degreeof twist may be employedjin making up the units A. The tighter thetwist, the greater will be the length of the yarns in a given length ofthe unit. -Any degree of pretwist of the group of units A may beemployed in making up the core B. When the group is pretwisted in thesame direction in which the strand is to be formed, i. e., to the left,the yarns will be longer in a given length of the core unit B and poundand A finished rope so made,

strand C than in the absence of such pretwi'st. When the group ispretwisted in the opposite direction, i. e., to theright, the yarns willbe shorter. According to the amount of right pretwist used, the group ofunits A may appear in the strand as of either right or left 'turn,because the right pretwist is partially lost or is reversed when makinga left turn strand.

The desired length of core yarn in a' given length of'strand may beachieved by means alone of the twist imparted to the elements in makingup the units or by means alone of the pretwist 'imparted to the group ofunits in making up the core or by combining and correlating the saidtwist and pretwist. In each casethe core yarns will all'be of 'equallength in a given length of strand. and all of them will bear a desiredpredetermined relation to the'length of the cover yarns in the samelength of strand.

In making all yarn rope, there are important practical advantages inusing core yarns and cover yarns that are of the same size and material.By this invention, identical yarns may be employed throughout the ropestructure, yet the tensile strain may be equalized on all yarns orvaried as desired between the core and cover yarns. The inventionlikewise has the practical.

advantage of permitting the cover yarns to have the same pitch in thestrand as the core units, while still subjecting the cover yarns to fulltensile strain and producing a rope of maximum strength. And similarly,wherever it is desired 'be made by twisting together ply-goods or groupsof yarns; but to achieve the full benefits of the invention, care shouldbe taken in making each u'nit to twist all of the elements in the grouptogether into substantially symmetrical helices about the axis of thatgroup and without center cable-laid'ropes such as drilling cables thisfoa-- Rope structures embodying the invention heroin described are foundto have advantagos not only in strength, durability and handling, butalso in elasticity, due perhaps to the absence of excess strain onindividual yarns or elements before the full strength of the rope isreached. In

ture of improved elasticity is of particular value and importance.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitationsshould be understoodtherefrom, but the appended claims are to be construed as broadly aspermissible in view of the prior art. The use of the terms right andleft in describing the twists of the various parts making up the ropestructure is to beunderstood as having reference to the structure `of aleft formed strand or right laid rope, but where a right formed strandor left laid rope is desired the opposite twists are intended andcovered. The term rope elements as used herein is intended to includeelements such as yarns, slivers, ply-goods, filaments, etc., made. offlbrous or filamentary materials appropriate for use in the manufactureof ropes,'rope Strands and the like. In rope strands used as singleunits-the cover elements may be twisted around the core in the directionopposite to that in which the core elements are twisted, to give desiredbalance to -the strand, and the lengthl of the cover elements in a givenlength of strand may be made -to bear a predetermined relation to thelength of the core elements in the same length of strand as abovedescribed, 'while preserving equality of length of all of the coreelements and such relation of pitch of the cover elements and core unitsas may be desired and predetermined.

I claim:

l. A rope strand comprising a plurality of units twisted together inhelices of substantially idenyarns or elements, and similarly to twistall the units together in Vsymmetrical helices in forming the strand, sothat the length of all elements in a given length of strand will besubstantially equal and will have the desired relationship to the lengthof the cover yarns or elements, if. any, in the same length of strand.

Fig. 5 illustrates a strand B made up of units A, each unit A being madeup of a plurality of ply-goods elements 10 and each element 20 beingmade up of a pluralityfof yams such as 21, 22 twisted together. Theyarnsmay be right turn i yarns plied or twisted together to the left orvice versa, or the twist of the ply may be in the same direction as theindividual twist of the yarns.

Fig. 6 illustrates a strand C with'cover yarns ll in'which the core B ismade up of units A and each unit A is made up of a plurality of slivers23 twisted together in helices of substantially equal diameter about theaxis of the unit.

Figs. 'i and a show the difference in pitch of` cover yarns and coreunits that may be achieved by pretwisting the group of units t o theleft or right before forming the same into a strand with cover yarnstical diameter about the axis of the strand, each unit consisting of aplurality of rope elements twisted together in helices of substantiallyidentical diameter about the axis of the unit without center elements sothaty all of the said'rope elements in a given length of strand are ofsubstantially equal length.

2. A rope strand comprising cover yarns and a core of rope elements, thecore comprising a plurality of units twisted together in helices ofsubstantially equal diameter about the axis of the strand, each unitcomprising a plurality of rope 'elements twisted together in helices ofsubstantially equal diameter about the axis of the unit without centerelements, and the pitch of the cover yarns in the strand bearing apredetermined relation to the pitch of the units in the strand.

3. An all` yarn rope strand comprising a plurality of units twistedtogether in helices of substantially equal diameter about the axis ofthe strand, each unit consisting of a plurality of yarns twistedtogether in helices of substantially equal diameter about the axis ofthe unit without center cover yarns in the stand bearing apredet'ermined relation to the pitch of the units in the strand.

5. An 'all yarn rope strand comprising core and cover yarns, the corecomprising a plurality of units twisted together-in helices ofsubstantially equal diameter about the axis of the strand, each unitcomprising a' plurality of yarns twisted together in helices ofsubstantially equal diameter about the axisv of the unit, and the pitchof the cover yarns in the strand being substantially equal to the pitchof the units in the strand.

6. An all yam rope strand comprising core and cover yarns, the corecomprising a plurality of units twisted'together in helices ofsubstantially equal diameter about the axis of the strand, each unitcomprising a plurality of yarns twisted together in helices ofsubstantially equalv diameter about the axis of the unit, and the lengthof the cover yarns in a given length of strand bearing a predeterminedrelation to the length of the core yarns in the same length of strand.

7. An all yarn rope strand comprising core and cover yarns, the corecomprising a plurality of units twisted together in helices ofsubstantially -equal diameter about the axis of the strand,

each unit comprising a plurality of yarns twisted together in helices ofsubstantially equal diameter about the axis of the unit, and the lengthof the cover yarns in a given length of strand being substantially equalto the length of the core yarns in the sanie length vof strand.

8. A rope strand comprising a cover of yarns and a core of ropeelements, the core comprising -a plurality of units twisted together inhelices of substantially equal diameter about the axis of the strand,each unit comprising a plurality of rope elements twisted together inhelices of substantially equal diameter about the axis of the unit, allof said rope elements in a given length of strand being' ofsubstantially equal length, and the pitch of the cover yams in thestrand bearing a predetermined relation to the pitch of the units in thestrand.

9. A rope strand comprising a cover of yarns and a core of ropeelements, the core comprising a plurality of units twisted together inhelices of' substantially equal diameter about the axis of the strand,each unit comprising a plurality of rope elements twisted together inhelices of substantially equal diameter about 'the axis 'of the unit,all of said rope elements in a given length of strand being ofsubstantially equal length, and such lengt bearing a predeterminedrelation to the length -of the cover yarns in the same length of strand.

10. A rope strand comprising a cover of yarns and a core'y of ropeelements, the core comprising a plurality of units twisted together inhelices of substantially equal diameter about the axisl 'of the strand,each unit comprising a plurality of rope elements twisted together inhelices of sub- 'stantially equal diameter about the axis of the unit,the pitch of the cover yarns in the strand bearing a predeterminedrelationl to the' pitch of the units inlthe strand and the length of thecover yarns in a given length of strand bearing a -predeterminedrelation to the length of the said rope elements in the units in thesame length of strand.

11. A rope strand comprising a cover of yamsV and a core ofrope,elements, the/core comprising a plurality of units twisted togetherin helices of substantially equal diameter about the axis of the strand,each unit 'comprising ,a plurality aeerose of rope elements twistedtogether in helices of substantially equal diameter about the axis ofthe units, the pitch of the cover yarns in the strand beingsubstantially equal to the pitch of the units in the' strand, and thelength of-the cover yarns being substantially equal to the length ofthesaid of strand.

12. A rope strand containing a core and a cover made entirely of yarnsof the same size and material, the core comprising a plurality of unitstwisted together to the left in helices of substantially equal diameterabout the axis of the strand, each unit comprising a plurality of yarnstwisted together to the left in helices of substantially equal diameterabout the axis of the unit and without center yarns, the covercomprising yarns formed' to the left about and 1- enclosing the core,the pitch of the cover yarns in the strand bearing a predeterminedrelation to the pitch of the core units in the strand, all of the coreyarns in a given length of strand being of substantially equal length,which length bears a predetermined relation to the length of the coveryarns invthe same length of strand.

' 13. A rope strand containing a core and a cover made entirely of yarnsof the same size and material, the 'core comprising a plurality of unitstwisted together to the left in heiices of substan- -tially equaldiameter about the axis of the strand, each unit comprising a pluralityof yarns twisted together to the left in helices of substantially equaldiameter about the axis of the unit and without center yarns, the covercomprising yarns formed to the left about and enclosiner thecore, thepitch of the cover yarns in the strand being equal to the pitch of thecore units in the strand, and all of the core yarns and cover yarns in agiven length of strand being of substantially equal length.- r

14. An all yarn rope, each strand comprising a plurality of core unitstwisted to the left with cover yarns, the pitch of the cover yarns inthe strand being the same as the pitch of the core units in the strand,the core units forming helices of equal diameter about the axis of thestrand, each core unit comprising a plurality of yarns twisted togetherto the left in helices of equal diameter about the axis of the unit, allof the yarns. including both the core yarns and the i in a given lengthof strand are of substantially :v equal length.

16. A cable laid rope as in claim 15 wherein each strand is providedwith cover yarns the length of which in a given Vlength of strand. is

substantially equal to the length of the rope elements of the core unitsin the same length of strand.

17. A rope strand comprising a cover and a core, the core comprising aplurality of units twisted together in helices of substantially equaldiameter aboutthe axis of the strand, each unit comprising a pluralityof rope elements twisted together in helices of substantially equaldiameter about the axis of theunit, the cover comrope elements in agiven length essnoae 5 prising rope elements twisted around the core,and the length of all of the rope elements in the core units of a. givenl'ensth of strand beln: sub-` in helices of substsntlslly equsl diameterabout m theaxis of the strand, each unit comprising a plurolity of-ropeelements twisted tosether in I helices of substantially equal diameterabout the sxis of the unit, all of said| rope elements in the core of e.given length of strand being of substanltinlly equsl length, and suchlength bearing a.

predetermined relation to the length of'the rope elements in the coverin the same length of strand. JOHN A. HETZEL.

